The present invention relates to a silver halide photographic material containing a synthetic high-molecular weight substance in a silver halide emulsion layer. More particularly, the present invention relates to a silver halide photographic material containing a latex in a silver halide emulsion layer.
Latices are currently used in combination with gelatin as binders in silver halide photographic materials in order to reduce the amount of gelatin needed and to provide coatings having improved properties such as those with respect to dimensional stability (both in the face of development and after exposure to wet heat), flexibility, pressure resistance and drying speed. However, the use of latices causes serious effects on photographic performance as manifested by the desensitization of emulsion, devitrification during development, color staining of dyes after development, and deteriorated quality of dots in the light-sensitive material used for making printing plates. Various proposals have been made with a view to solving these problems. According to U.S. Pat. No. 3,525,620, Belgian Patent No. 768,558, U.S. Pat. Nos. 3,142,568 and 3,325,286, Belgian Patent No. 708,347, German Patent No. 2,049,150, British Patent No. 1,498,697 and Japanese Patent Publication No. 5331/1970, 50969/1984 (the term OPI as used hereinafter means an Unexamined Published Japanese Patent Application); it is proposed that the aforementioned problems be solved by polymerizing latices with specified activating agents. However, these methods are applicable to only limited types of emulsions and none of them can be practiced without causing adverse effects on fogging, sensitivity and development characteristics. Latices may be emulsion-polymerized in the presence of low-molecular weight surfactants but this method can be applied to only limited combinations of latices and silver halide emulsions and, in addition, the amount of latices that can be incorporated in the emulsion is also limited.
Japanese Patent Application (OPI) No. 50240/1980, Japanese Patent Publication Nos. 47371/1980 and 19772/1979, and Japanese Patent Application (OPI) Nos. 52882/1973 and 52883/1973 disclose techniques which attempt to solve the aforementioned problems by incorporating in silver halide emulsions those latices which have been emulsion-polymerized in the presence of a high-molecular weight protective colloid. These latices do not cause substantial adverse effects on photographic performance but they present problems associated with the fabrication of photographic materials such as devitrification during development, increase in the viscosity of coating solutions, difficulty in applying more than one layer simultaneously, and cissing during the coating operation. In short, from the viewpoint of photographic performance, polymer latices protected with high-molecular weight colloids are advantageously employed in order to provide coatings having improved properties but these latices have many problems associated with the manufacturing process such as devitrification during development and the increase in viscosity or occurrence of cissing during coating operations. Photographic materials employing latices that are protected with high-molecular weight colloids have not yet been commercialized.